Method and a device for bonding two plate-shaped objects

ABSTRACT

A method for bonding two plate-shaped objects ( 5 ) with an adhesive which is cured by ultraviolet light irradiation and by heating. The two plate-shaped objects ( 5 ) with the adhesive in between are transported into a cure chamber ( 11 ) comprising an ultraviolet lamp ( 12 ) and a heating element ( 13 ). A moveable heat-shielding member ( 3 ) is temporary present between the objects ( 5 ) and the heating element ( 13 ) during at least the first part of the irradiation treatment. Preferably, the heat-shielding member ( 3 ) is positioned outside the cure chamber ( 11 ) during a part of the curve treatment.

The invention relates to a method an a device for bonding twoplate-shaped objects with an adhesive which is cured by ultravioletlight irradiation and by heating. Such method can be used in themanufacture of a so-called SOA-semiconductor device(Silicon-On-Anything-semiconductor device) for bonding a disc-shapedsemiconductor substrate to a disc-shaped insulating carrier, such as aglass carrier.

U.S. Pat. No. 6,051,481 discloses a method for dispersing an adhesivebetween two plate-shaped objects, whereby the two objects are rotatedwhile being pressed together, so that the adhesive between the twoobjects spreads homogeneously under the influence of the centrifugalforce acting on the adhesive. After adhesive is applied between twoobjects, according to U.S. Pat. No. 6,051,481 or in any other way, itmay be required to cure the adhesive by ultraviolet light irradiationand/or by heating, depending on the type of adhesive. The inventionrelates to a method whereby both treatments, light irradiation as wellas heating, are applied.

It is advantageous to make use of only one cure chamber in which thecuring treatment of the adhesive takes place. Thereby both theirradiation lamp and the heating element must be present in the curechamber, for irradiating and for heating the adhesive between the twoobjects.

In case the two plate-shaped objects have a different coefficient ofexpansion, the bonded objects may be warped or curled because during thecuring treatment the temperature of the objects is different (higher)from the temperature of the bonded objects afterwards.

The object of the invention is to decrease the tendency of warping orcurling of the bonded plate-shaped objects.

In order to accomplish that objective, the two plate-shaped objects withthe adhesive in between are transported into the cure chamber—comprisingan ultraviolet lamp and a heating element—whereby a movableheat-shielding member is temporary present between the objects and theheating element during at least the first part of the irradiationtreatment. Thereby the adhesive will bond together the two plate-shapedobjects to a certain degree before the temperature of the objects willsubstantially increase.

Because the temperature in the cure chamber will be higher thetemperature outside the cure chamber, preferably, the movableheat-shielding member is positioned outside the cure chamber during apart of the cure treatment, so that the heat-shielding member can cooldown

In one preferred embodiment, the heat-shielding member is a portion of(or attached to) a carrier for transporting the said objects into thecure chamber. Thereby the objects and the heat-shielding member willenter into the cure chamber at the same time. Thereupon the carrier mayremain in the cure chamber for at least 30 seconds, preferably for morethan 60 seconds, and subsequently the carrier is removed out of the curechamber while the said objects remain in the cure chamber for at least60 seconds.

Preferably, the said objects are moved in the direction of the heatingelement after the carrier has been removed out of the cure chamber, sothat the objects can be heated quickly to the desired temperature.

Preferably, the method for bonding two plate-shaped objects with anadhesive which is cured by ultraviolet light irradiation and by heatingcomprises the following steps: (a) moving two plate-shaped objects withan adhesive in between into a cure chamber comprising an ultravioletirradiation lamp and a heating element, (b) keeping a heat-shieldingmember between the said objects and the heating element during at least30 seconds while the said objects are exposed to ultravioletirradiation, (c) removing the heat-shielding member for at least 60seconds while the said objects are heated by the heating element, and(d) removing the said objects out of the cure chamber.

The invention also relates to a device for bonding two plate-shapedobjects with an adhesive which is cured by ultraviolet light irradiationand by heating, comprising a cure chamber with an ultravioletirradiation lamp and a heating element, and comprising a movableheat-shielding member which can be temporary present between the heatingelement and the said two plate shaped objects.

The invention will be explained in more detail hereinafter by means of adescription of an embodiment, in which reference is made to a drawing,in which:

FIG. 1 is a top view showing a carrier;

FIG. 2 is a side view of the carrier;

FIG. 3 is a bottom view of the carrier;

FIG. 4 is a top view of the carrier carrying two plate-shaped objects;

FIG. 5 is a side view of the carrier according to FIG. 4;

FIG. 6 is a side view of the carrier in a different position;

FIG. 7 shows a cure chamber with the carrier inside; and

FIG. 8 shows the cure chamber with the carrier outside.

The figs. are merely schematic representations of the embodiment, inwhich less relevant parts are not shown.

FIGS. 1-3 show a carrier comprising a arm 1 bearing at its end a supporttable 2 having a substantially round and flat upper surface. Underneaththe support table 2 a heat-shielding member 3 is attached to it. Theheat-shielding member 3 is a disc-shaped member made of heat insulatingmaterial. Arrow 4 indicates the direction of movement of the carrier1,2.

FIGS. 4 and 5 show the carrier 1,2 according to FIGS. 1-3, whereby thecarrier is carrying two plate shaped objects 5. The two plate-shapedobjects are both disc-shaped and are provided with a layer of adhesivein between. The layer adhesive has to be cured by ultraviolet lightirradiation as well as by heating. The carrier 1,2 can move in thedirection indicated by arrow 4 to transport the two objects 5 into acure chamber and afterwards out of the cure chamber 11 (FIGS. 7 and 8).

Within the cure chamber there are three support bars 6 having a verticalportion 7 and a horizontal portion 8 (see FIG. 5). The support bars 6can move in vertical direction as indicated by arrows 9. Thereby thehorizontal portions 8 of the support bars 6 can lift the objects 5 fromthe support table 2, so that the carrier can move (arrow 4) leaving thetwo objects 5 in the cure chamber 11. Thereby the objects are carried bythe support bars 6 as shown in FIG. 6.

FIGS. 7 and 8 show the cure chamber 11 containing an ultravioletirradiation lamp 12 in its upper part and a heating element 13 in itslower part. The cure chamber 11 is provided with an opening 14 throughwhich the carrier 1,2—together with the heat-shielding member 3 attachedto it—can be moved into and out of the cure chamber 11. Arrow 4indicates the direction of movement.

FIG. 7 shows the carrier 1,2 after it is entered into the cure chamber11. The carrier 1,2 carries two plate shaped objects 5 as already shownin FIG. 5. After entering the cure chamber 11 the two objects 5 areirradiated by the ultraviolet lamp 12 to cure the layer of adhesivebetween the objects.

To prevent the two objects 5 from heating during the first part of thecure treatment, the carrier 1,2 is provided with the heat-shieldingmember 3 in such way that the heat-shielding member is located betweenthe two objects 5 and the heating element 13 in the lower part of thecure chamber 11. So, as long as the carrier 1,2 is inside the curechamber 11, the two objects 5 shall not be heated by the heating element13, at least the heating will be reduced.

After the first part of the cure treatment has taken place, the twoobjects 5 are lifted from the carrier 1,2 by the three support bars 6(as shown in FIG. 6), so that the carrier 1,2—together with theheat-shielding member 3—can be moved out of the cure chamber 11.Subsequently the three support bars 6 are moved downward to bring thetwo objects 5 closer to the heating element 13, whereby the objects 5may rest on the heating element 13. Thereby the support bars 6 may moveinto recesses (not shown) in the heating element 13. After the curetreatment is completed the three support bars 6 move upwardly, so thatthe carrier 1,2 can move back into the cure chamber 11. Then the supportbars 6 replace the objects 5 on the carrier 1,2 and the objects 5 can betransported by the carrier 1,2 out of the cure chamber 11.

The described embodiment of the device for bonding two plate shapedobjects is merely an example, a great many other embodiments arepossible.

1. A method for bonding two plate-shaped objects with an adhesive whichis cured by ultraviolet light irradiation and by heating, whereby thetwo plate-shaped objects with the adhesive in between are transportedinto a cure chamber comprising an ultraviolet lamp and a heatingelement, whereby a movable heat-shielding member is temporarily presentbetween the objects and the heating element during at least a first partof the irradiation treatment.
 2. A method as claimed in claim 1,characterized in that the movable heat-shielding member is positionedoutside the cure chamber during a part of the cure treatment.
 3. Amethod as claimed in claim 1, characterized in that the heat-shieldingmember is a portion of a carrier for transporting the said objects intothe cure chamber.
 4. A method as claimed in claim 3, characterized inthat, during the cure treatment, the carrier remains in the cure chamberfor at least 30 seconds, preferably for more than 60 seconds, and thatsubsequently the carrier is removed out of the cure chamber while thesaid objects remain in the cure chamber for at least 60 seconds.
 5. Amethod as claimed in claim 4, characterized in that the said objects aremoved in the direction of the heating element after the carrier has beenremoved out of the cure chamber.
 6. A method as claimed in claim 1,characterized by the following steps: (a) moving two plate-shapedobjects with an adhesive in between into a cure chamber comprising anultraviolet irradiation lamp and a heating element; (b) keeping aheat-shielding member between the said objects and the heating elementduring at least 30 seconds while the said objects are exposed toultraviolet irradiation; (c) removing the heat-shielding member for atleast 60 seconds while the said objects are heated by the heatingelement; (d) removing the said objects out of the cure chamber.